How to upgrade from 20amp circuit to 30 amp

Old 06-09-03, 08:56 PM
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How to upgrade from 20amp circuit to 30 amp

hi guys,

sorry this might be a stupid question but
i have never done any electrical work.
Currently I have an outlet which is 220/230 volts
and 20amp circuit. (the plug type is C type).
I need to install A/C which is 18000 BTU
and uses D type outlet.

My panel is just uses the circuit breakers type switch. Is it something that should be easily done by me or do i need an electrician? how much a job like this would cost?
I guess he does not need to rewire...correct?

The reason I am doing this is to install one of those A/C Hot and Cool units to bring extra warmth in the house in winter. (the unit is 17000 BTU). I assume I will get more heat out of this unit than
an electric fireplace which I guess puts
out 5000 btu.

Is it worth the hassel or should I stay with existing "old" Unit which is
20 amp 15000 Btu (no heat).

Thanks again for your response.

Old 06-09-03, 09:43 PM
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No stupid questions. Yes this will be a job for an electrician. Not only will he/she have to change the outlet, they will have to change the wire and the circuit breaker. A circuit breaker panel is no place for a novice. The wire will need to be changed because in all likelyhood, it was sized for the 20A original circuit. By increasing the size of the A/C unit, you have increased the current and therefore the required wire size. The breaker will also have to be increased to keep from tripping constantly. Hire a good electrician and save yourself some headaches.

Scott E.
Old 06-09-03, 09:45 PM
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Alex, please tell us what country you are in. Neither C nor D plugs are used in the United States. I don't even think C and D plugs are used in many (if any) English-speaking countries.

Conversion from C to D requires a grounding connection. If there is not already a grounding connection in the box, adding one might be difficult. How difficult depends on how far it is from this receptacle to the load center (or whatever they call a the box that has the breakers in it in your country). If there is already a ground, it might be easy.
Old 06-09-03, 10:03 PM
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Thanks for your replies....

John, I am in good old USA (Boston , MA).

Hmm, Maybe I described it wrong. The
plug type is "opposed" vs "large Tandem".
I have seen it refered as C or D plug type. Most of the 15000 + BTU units which uses 20A uses Opposed type and that is the one
which i have now, and I would like to go to
30A which the unit requires for the heat
strips. I think there maybe some work involved on the main panel but I was hoping the existing wire from the panel to the oulet did not have to be replaced. (i think it is 12 gauge wire, not sure)...
I only have 1 free slot left on the main panel,but I think some of the levers can be changed in to mini circuit breakers... Anyway, I am hoping by
adding the 30 amp circuit, I can put 10-15 k
BTU in my house. Some one told me, this is
bad idea because the these Heat/Cool A/C units
are not designed to be a primary source of

PS. so, what would be a typical cost of a job
like this? I will get couple of quotes..but
just curious.

Old 06-09-03, 10:12 PM
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Alex, go to this site and pick out the receptacle and plugs to which you refer.

Cost will depend very heavily on how far it is from the receptacle to your panel, and what is in between. It could also depend on whether any upgrades will be required. And as I'm sure you already know, Boston doesn't have the cheapest labor rates around.

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